MIT researchers are designing sensors that use carbon nanotubes to detect hazardous gases.

Using carbon nanotubes, MIT chemical engineers have designed the most sensitive electronic detector yet for sensing deadly gases such as the nerve agent sarin. This sensor could prove to be critical in the protection against bioterrorism. The sensor has demonstrated high sensitivity in detecting minute traces of molecules mimicking nerve toxins. It could also detect mustard gas, ammonia, and so on.

To build the detector, Strano and his team used carbon nanotubes (diameter about 1/50,000 of the width of a human hair) aligned across microelectrodes. When a particular gas molecule binds to the carbon nanotube, the tube's electrical conductivity changes. The low sensitivity was reached pairing the nanotubes with a miniature gas-chromatography column placed onto a silicon chip smaller than a penny. The column rapidly separates different gases before feeding them into the nanotubes.

Sarin, which killed 12 people in a 1995 terrorist attack on the Tokyo subway, can kill at very low concentrations after 10 minutes. And Al-Qaeda came close to using deadly gas in the New York City subway system, according to a book called The One Percent Doctrine.

According to MIT's site, this technology could also be used in cheaper, low-energy pocket-sized gadgets. "We think this could be applied to a variety of environmental and security applications," said Michael Strano, the Charles and Hilda Roddey Associate Professor of Chemical Engineering.

One sensor could run a very long time on a regular battery. "It's something that could sit in the corner of a room and you could just forget about it," Strano said.